DESCRIPTION: The investigators propose to evaluate two versions of choice-making procedures (concurrent operants), one during assessment and one during treatment, as a continuation project. To date, they have shown that a treatment package involving functional analysis and functional communication training (FCT) has been successful in suppressing aberrant behavior, inducing prosocial behavior, and promoting stimulus generalization. In this proposed project, they will evaluate key elements of both the assessment and the treatment aspects of their model with 20 children over a 4-year period. During assessment, they will conduct a concurrent operants assessment to test the relative influence of negative and positive reinforcement on prosocial behaviors (e.g., social interaction, time allocation with parent). These results will be compared with the results of the functional analysis of aberrant behavior to evaluate the correspondence between the two assessment methodologies. During treatment, they will evaluate whether standard FCT treatment is enhanced when children are provided with choices. They will compare their current FCT treatment with a FCT plus choices treatment within a reversal design to determine whether the FCT plus choices treatment reduces the need for parents to implement extinction and mild punishment procedures. During post-treatment, the investigators will conduct a component analysis to evaluate whether the positive and/or negative reinforcement variables identified via the concurrent operants assessment influence the maintenance of treatment effects. The application addresses the issue of interaction between positive and negative reinforcement. This interaction will be evaluated in two ways. First, during assessment, they will study if positive reinforcers maintain adaptive behavior even when negative reinforcement is shown to maintain aberrant behavior. One clinical implication of this finding would be the need for positive reinforcers to be incorporated more directly into long-term maintenance. Second, they will study if distinct types of treatment components, such as choices, are relatively more effective for different functional categories of aberrant behavior (i.e., behavior maintained by positive or negative reinforcement).